Mine prop



v June 19, 1928.

c'. GA'scARD MINE PROP Filed Oct. 13, 1926 Una-'6127197' Patented June 19, 1928. Y y

UNITED STATES PATENT OFFICE.

C BLABLES GASCABD, F WIESBADEN, GERMANY.

MINE raor. l

Application fled Dotober 18, 1926, Serial No. 141,402, and in Germany June 3, 1928.4

f My invention relates to a yielding mine prop composed of two profile irons the faces of which can be made to slide upon each other, and are held in rictional contact with 6 each other by means of a double-armed clamp oscillative upon one prop member. This clamp is adapted to slideupon its ivot and thereby vary the respective lengt its two lever arms. My invention resides in l0 the feature that one end 'of the oscillatory clamp affects, by means of4 an eccentric, the

movable prop member in suc-h a manner that when the load on the prop exceeds the pressure limit to which the prop has been initial-A l ly adjusted, the eccentric, in consequence ofl the cooperation of the movable member,'is revolved by the latter and resses it with increased force against the' stationary prop member, the pressure on which is consequently transmitted over a frictional surface which increases in proportion to the yielding eii'ect. In a further torn; of application of my invention the eccentric is provided with a Wedgeshaped stop tangential to the point of maximum eccentricity, which as the pressure increases eventually presses with its one wedge-face flat against the movable prop member, and the opposite wedge-face of which serves as point of application for a hammer when the prop is being set into its initial operative position. Within thisy tangential stop and lon the face of it which is turned away fromthe prop there isfurther provided an orifice for the introduction of a. lever serving to turn back and thereby to release the eccentric.

The yielding mine prop as constructed acucording to my invention has the advantage of consisting entirely of metal, and thus has no wooden parts susceptible to the eifects of dampness and the weather, and is not dependent for its adjustment upon screws or such like separate parts. Owing to the pvoting point of the double-armed7 lever being made free to slide in thev manner described, it is `possible for the'mine prop as herein described by altering'the length of the lever-arm and by varying the initial setting of the eccentric, to be adjusted for differentyield limits and also'for varying maximum loads and varying yield extents. The eccentric lbeing mounted on an oscillatory lever, the initial pressure exercised when the eccentric is moved lies rather high, and since the eccentric asthegzield increases af- VfectsVV an increasing frictional s tween both prop members, a slight turning www movement producedpby the cooperation ofA..

the movable prop member is always sufficient to set the prop anew for increasing pressures, and this in such a manner that the` prop is not deprived of its property of being a yielding mine prop.

I will now describe m invention with reference to the drawing orming a part of this application, and in which 4 Fig. 1 is an elevation of a complete prop.

Fig. 2 is a similar partial view on an enlarged scale, and F Fig 3 is a section along the line 3-3 of The mine prop consists of two parts 1. and 2, preferably of equal length and made from iron I-beams. 'The stationary prop member 2 is provided with a pair of base-brackets 2, and the movable prop meniber 1 with a pair of `brackets 1L for the wooden cross pieces of the match-boarding ofthe mine roof. The guide straps 3, 3 serve to maintain in connection and in mutual position the two opposed tlanges of both prolile irons `1 and 2. Through the upper part of the stationary prop member 2 which is strengthened by disks 4a there passes a pivot bolt 4, on which is mounted oscillatively by means .of a slot 5, a double-armed clamp `6. This clamp 6 .embraces both prop members' 1 and'2, ex'- tending with its twov ends beyondei-ther. 0n the one end of the oscillating clamp 6 is loosely mounted on a boltl 7 an abutment member-8 lying with its right-angled abutment surface against the'out'er flange of the stationary prop member 2. On the opposite. end of clamp 6 yis oscillatively mounted on a bolt 9 an eccentric 10, which is tangentially at the pointof its maxlmum eccentricity, with al wedge-shaped enlarge-` ment 10a adapted to act as a stop. f When the' prop iserected and set as .shown in Fig. 1, the wedge-shaped stop is out of contact with provided, Y

the movable prop member 1. When the prop is subjected to the maximum pressure or` load, the pressure transmitting eccentric 10 is turned, to the point of its maximum eccenf .rear surface of the stop 10 and the movable prop member 1 is, owing t'o the acute-angled position of the stop 10 so great, that every increase in the load rtends to eiectf: an os'- llationJethe-doublearmed damp 6, by

l eccentric l0, there is which the friction between the two prop members l and 2 is still further increased.

rIhe settin of the prop at the time of erection is e ected by strokes of a hammer on the front surface of stop 10B, i. e. the surface turned away from prop member l. To enable the operator to readil release the provided in that thickened Vpart of it which forms the wedgeshaped stop l0, an orifice l1 for the introduction of a lever of any required length.

The lower yielding limit depends upon the initial operative setting of the prop, i. e. on the degree to which eccentric 10 is being driven in, and the extent of the yield on the length of the eccentric operative surface of the eccentric 10. By varying the respective length of the lever-arms of the double-armed clamp 6 it is possible to set the initial operative point of the eccentric 10 either nearer to or remoter from the point of maximum eccentric throw, for example, by interchanging the abutment member 8 for a" thicker one, or by setting it back from the flange of pro y member 2 by interposed plates. As wit every oscillatory movement of the' doublearmed clamp 6 the friction between abutment 8 and rop member 2 has to be overcome, the a justment of the prop may be altered by increasing or decreasing size of the rictional surface, i. e. by making abutment 8 longer or shorter, respectively.

What I claim as my invention and desire to secure by Letters Patent of the United States is l. A mine prop, comprising, in combination, a stationary and a movable prop member, the latter being adapted to yield longitudinally with respect to the stationary member under load, an oscillatory clamp member having a pivotal connection with the stationary member and adapted to maintain said prop members in mutual frietional contact with each other, an eccentric in coopera tive contact with said movable prop member and revolubly mounted at one end of said clamp member toexert an increasing pressure against said pro member Aupon movement t ereof under its lbad causing said eccentric to revolve, and an abutment member mounted at the other end of said clamp member and between said other end and said stationar member, thereby to maintain said other en in operative relation with respect to the prop members.

2. A mine prop, comprising, in combination, a stationary and a movable prop member, the latter being adapted to yield longitudinally with respect to the stationary memberunder load,an oscillatory clamp member having a pivotal connection with said stationary prop member and adapted to maintain said rop members in mutual frictionalI ,w, --eontact'witlreaclrotmr- Y mcuun4t9vvry operative length of the clamp member, an

eccentric in cooperative contact with said movable prop member and revolubly mounted at one end of said clamp to exert an increasing pressure against said prop member upon movement of the said prop member under its load causing said eccentric to revolve, and an abutment member mounted nally with respect to-tlie stationary member under load, an 4oscillatory clamp member having a pivotal mounting on said stationary prop member and adapted to maintain saidprop members in mutual frictional contact with each other, an eccentric in cooperative Contact with said movable pro' member and revolubly mounted at one en of said clamp member to exert an increasing pressure against the movable prop member upon movement of said prop member under its load causing said eccentric to revolve, an abutment member loosely mounted at the other end of said clamp member to maintain itself against the stationary rop member during movement of said mova le prop member, said eccentric having a projecting portion Aprovided with a fiat surface disposed tangentially to the point of maximum eocentricity of the eccentric, Asaid tangential surface tlatl en aging said movable pro member w en t e latter is subjected to maximum load.

vthe latter being adapted to yield longitudiz ative contact with said movable pro member and revolubly mounted at one en of said clamp member to exert an increasing pressure against the movable prop member upon movement of said prop member under its load' causing said eccentric to revolve, an abutment member 'disposed at the other-,yv end of said clamp member normally to maintain said otherend of the clamp in operative relation with respect to the stationary prop member, said eccentric having a projecting portion provided withV a flat surface disposed tangentially to the point of maximum 1 eccentricity' of said eccentric, said surface4 flatly engaging against the movableprop memberwh'en the latter is subjected to maximum load, another.` surface onsaid pro- ]ection providing a Dolntgpiapplicatiopgior e. hammer '1n initially visett'inghthe" propV in operative position.

5. A mine prop,- comprisin in combination, a stationary and amova le prop member, the latter being adapted to yield longitudinally with respect to the' stationary member under load, an oscillatory clampmember having a pivotal mounting on said' stationary prop member and adapted to maintain said prop members in mutual frictional contact with each other, an eccentric 1n cooperative. contact with said movable prop member and. revolubly mountedA at one tionary prop member,-.'a projecting portion i formed on saideccentric' and havlng a flat surface disposed tangentially to the point of maximum eccentricitylof saideccentric, saidA surface flatly contacting against said movable prop member when the latter is subjected to maximum load, said projecting portion being provided with means adapted to receive an eccentric release lever.

Y 6. A mine prop, comprising, in combina tion, a stationary and a movable prop member, the latter being adapted to yield longitudinally with respect to the stationary member under load, an oscillatory clamp member having a pivotal mounting on said station-v Aary prop member and adapted to maintain said prop members in mutual frictional con- -tact with each other, an eccentric in cooperative contact with said movable member to exert an mcreasln v pressure against the l movable prop mem r upon movement of said prop member under its'load causing said eccentric to revolve, Aan abutment member mounted between the other end of said clamp member and 4stationary-prop member, there- Y by to maintain saidclamp in operative rela'- tion with respect to the stationary prop member, a projecting portion on .said eccentric, having a at surface disposed tangentifallg to the point of maximum eccentricity o 4t vided with a surface serving as a point of e eccentric, said projection being prof a plicationfor a hammer to be used in set- I tingthe prop in its initialoperative position,

and hav1ng.therein .an orifice for thel insertion of an eccentric release lever.

CHARLES GASCARD.. 

